My interests span the coastal zone, from seacliff erosional processes to sediment dynamics in the shallow coastal ocean. My research focuses on the quantitative study of hydrodynamics, sediment transport, and geomorphology in coastal and marine environments.

Biography

2002-present Research Geologist and OceanographerCoastal and Marine Geology Program, US Geological Survey

2002-present Research AssociateInstitute for Marine Sciences, University of California at Santa Cruz

2002-2004 Research FellowPartnership for Interdisciplinary Studies of Coastal Oceans Consortium

2000-2002 Post-doctoral ResearcherInstitute for Marine Sciences, University of California at Santa Cruz

The influence of physical processes on coral and bedrock reef habitats and ecosystems

The inner shelf comprises important hard (coral and bedrock) and unconsolidated sedimentary (sand and mud) habitat for many species of concern and commercial interest (including fish, benthic invertebrates and marine mammals). It is also these coastal environments that have been most impacted by infrastructure development, nutrient and contaminant delivery, and natural and human-induced sedimentation. The high geomorphic and hydrodynamic complexity both within and between coral and bedrock reefs, in conjunction with past technical restrictions, has limited our understanding of the nature of flow and the resulting flux of physical, chemical, and biologic material in these ecosystems. Understanding the physical controls on the timing and magnitude of flow and sediment, larvae, nutrient, and contaminant transport, along with their impact on seafloor geomorphology, stability, and sedimentation in these refugia are essential to assessing modern anthropogenic impacts (climate change, etc.) on these ecosystems.

This research utilizes in situ time-series instrumentation, water column profilers, GPS drifters, numerical modeling, and repetitive geophysical mapping to try to better understand the influence of meteorologic and oceanographic forcing on hydrodynamics and the resulting water column properties and seafloor geomorphology. The goal is to clarify the connection between hydrodynamics, geologic processes, and the resulting changes in habitat and population dynamics of shallow water coral and bedrock reef biological communities.

The current study sites include Central California, Puerto Rico, and the Hawaiian, Mariana, Virgin, and American Samoan Islands.

The influence of climate change and sea-level rise on low-latitude carbonate coasts

Observations show that sea level is rising globally and recent estimates suggest sea level will exceed 1.0 m, and may reach 2.0 m, above 2000 levels by the end of the 21st century. Sea-level rise is particularly critical for unconsolidated low-lying carbonate islands, many of which have maximum elevations of less than 4 m above present sea level. Such islands are Holocene features that support 2000-year-old cultures, yet the amount of land and water available for human habitation, water and food sources, and ecosystems is limited and extremely vulnerable to inundation from sea-level rise. Storm wave-induced overwash and inundation threatens terrestrial infrastructure and may contaminate the thin freshwater lens underlying islets with saltwater, making the islands unsuitable for agriculture and/or habitation. Rising sea levels will further exacerbate the impacts of storms and wave action on low-lying carbonate islands by reducing wave breaking (and thus energy dissipation) at the reef crest and result in greater wave energy impacting the shoreline. Understanding the physical controls on the timing and magnitude of overwash and inundation, along with their impact on coastal geomorphology are essential to assessing impacts on islands' infrastructure and ecosystems.

This research utilizes in situ time-series instrumentation, numerical modeling, and repetitive geophysical mapping to try to better understand the influence of meteorologic and oceanographic forcing on hydrodynamics and the resulting overwash and geomorphology. The goal is to clarify the connection between projected future wave and wind forcing, sea level, and the resulting oceanographic and geologic processes on low-latitude carbonate coasts.

The current study sites include Northwestern Hawaiian and Marshall Islands.

Connectivity among individual marine protected areas (MPAs) is one of the most important considerations in the design of integrated MPA networks. To provide such information for managers in Hawaii, USA, a numerical circulation model was developed to determine the role of ocean currents in transporting coral larvae from natal reefs throughout the...

Many low-elevation, coral reef-lined, tropical coasts are vulnerable to the effects of climate change, sea level rise, and wave-induced flooding. The considerable morphological diversity of these coasts and the variability of the hydrodynamic forcing that they are exposed to make predicting wave-induced flooding a challenge. A process-based wave-...

Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future...

Five passive membrane samplers were deployed for 28 continuous days at select sites along and near the west Maui coastline to assess organic compounds and contaminant inputs to diverse, shallow coral reef ecosystems. Daily and weekly fluctuations in such inputs were captured on the membranes using integrative sampling. The distribution of organic...

The coastal and upslope terrains of West Maui have had a long history of impacts owing to more than a century of human activities. Resource extraction, agriculture, as well as residential and resort development have caused land-based pollution that impairs water quality and adversely impact the adjacent marine ecosystem. Today, West Maui’s coral...

The degradation of coastal habitats, particularly coral reefs, raises risks by exposing communities to flooding hazards.
The protective services of these natural defenses are not assessed in the same rigorous, economic terms as artificial
defenses such as seawalls, and therefore often not considered in decision-making. Here we present a new...

Many tropical islands and coasts are lined with coral reefs. These reefs are host to valuable ecosystems that support
abundant marine species and provide resources for fisheries and recreation. As a flood defense, reefs protect coastlines
from coastal storm damage and flooding by reducing the majority of incident wave energy. However, during storm...

There is little information on the oceanography in the National Park of American Samoa (NPSA). The transport pathways for potentially harmful constituents of land-derived runoff, as well as larvae and other planktonic organisms, are driven by nearshore circulation patterns. To evaluate the processes affecting coral reef ecosystem health, it is...

Land-based sediment and contaminant runoff is a major threat to coral reefs, and runoff reduction efforts would benefit from knowledge of specific runoff sources. Geochemical signatures of small drainage basins were determined in the fine fraction of soil and sediment, then used in the nearshore region of a coral reef-fringed urban embayment on...

The presence of large bottom roughness, such as that formed by benthic organisms on coral reef flats, has important implications for the size, concentration, and transport of suspended sediment in coastal environments. A 3 week field study was conducted in approximately 1.5 m water depth on the reef flat at Ningaloo Reef, Western Australia, to...

Very low frequency (VLF, 0.001–0.005 Hz) waves are important drivers of flooding of low-lying coral reef-islands. In particular, VLF wave resonance is known to drive large wave runup and subsequent overwash. Using a 5 month data set of water levels and waves collected along a cross-reef transect on Roi-Namur Island in the Republic of the...